"The President's decision to go outside the bounds of the law to try to get what he failed to achieve in the constitutional legislative process violates the Constitution and must be terminated," Pelosi wrote in a letter sent to lawmakers earlier in the week.

"We have a solemn responsibility to uphold the Constitution and defend our system of checks and balances against the President's assault."

Senate Minority Leader Chuck Schumer supported Pelosi Thursday in a statement urging legislators to support the House resolution.

“This issue transcends partisan politics, and I urge all senators – Democrats, and Republicans – to support this resolution to terminate the president’s emergency declaration when it comes up for a vote in the Senate,” Schumer said.

“Identical companion legislation to the House resolution will soon be introduced in the Senate.”

The move could force Trump's first-ever veto.

Speaker Pelosi asks Democrats to back one page resolution to overturn Trump national emergency declaration on border wall pic.twitter.com/RbS9fUHHEg